A senior Russian lawmaker has proposed changing the constitution, in a move that might allow President Vladimir Putin to stay in power longer.

But a Kremlin spokesman responded by saying Mr Putin was opposed to any such change to the constitution.

Federation Council Speaker Sergei Mironov said that instead of four years the presidential term should be extended to "five, or maybe seven".

He also argued against the two-term limit for the Russian president.

Under the current rules Mr Putin will have to step down in 2008, after having served two terms.

"We proceed from the president's position that it is pointless to change the constitution to extend the presidential term or the number of terms," said Kremlin spokesman Dmitri Peskov, quoted by the Associated Press.

Mr Putin has made it clear previously that he is not planning to seek a third term - despite calls from various politicians and organisations for him to do so.

But Mr Mironov, speaking immediately after his re-election as Speaker of the upper house, said the constitutional amendment proposal should be discussed by lawmakers throughout Russia and then put to Mr Putin for approval.

Mr Mironov has been Speaker since January 2003. He represents the St Petersburg assembly - the city where Mr Putin also launched his political career.

Mr Putin's second term in office expires in 12 months' time. But the BBC's James Rodgers in Moscow says it is not clear whether any of the changes Mr Mironov seeks could be introduced before the election in March 2008.